All over the planet, temperature increases are affecting wildlife. Some species are spreading to new areas. For others, climate change means extinction. THE NATURE OF THINGS with David Suzuki presents Warnings From The Wild, a documentary that draws together recent evidence of the effects of the biggest climatic upheaval in 10,000 years.

In the Arctic, climate changes are tangible. As the Earth warms, the ice caps melt. Polar bears depend on the ice to hunt. If the ice breaks up in early spring, the bears go hungry and scientists have noticed a change in the bears' weight and survival rate of cubs. At the other end of the world in the Antarctic, the pattern is repeated, only it's penguins that depend on the ice.

On Banks Island in the western Arctic, the Inuvialuit people of Sach's Harbour describe dramatic changes in their environment, directly related to temperature rise. As individual and communal observers of their northern environment, the Inuvialuit may not be scientists in the strict sense of the term, but like aboriginal peoples all over the world, a complete understanding of their harsh environment has been key to their survival. Today, they are seeing changes never before described by ancestors.

In the more temperate zones of Europe and the United States, scientists are using the long-term records of amateur naturalists to show how trees are leafing and birds are migrating a full two weeks earlier.

To the south, the cloud forests of Costa Rica, home of the famed Golden Toads of Monteverde, have subtly changed, leading to the toads' extinction. On the equator, mile after mile of coral reef is under threat. Exclusive footage shows the awesome but sinister beauty of doomed coral reef. In the Maldives, scientists have detected signs of coral recovery, but if the sea temperatures continue to warm, the coral will begin to die. There is still time to prevent coral extinction as well as other impending environmental disasters, but only if nature's warnings are heeded.